From dcb23f439f3cf5601fb8bf49889accd16f3b30a1 Mon Sep 17 00:00:00 2001 From: Eric Botcazou Date: Wed, 5 May 2021 16:50:55 +0200 Subject: [PATCH] Fix PR rtl-optimization/100411 This is the bootstrap failure of GCC 11 on MinGW64 configured with --enable- tune=nocona. The bottom line is that SEH does not support CFI for epilogues but the x86 back-end nevertheless attaches it to instructions, so we have to filter it out and this is done by detecting the end of the prologue by means of the NOTE_INSN_PROLOGUE_END note. But the compiler manages to generate a second epilogue before this note in the RTL stream and this fools the aforementioned logic. The root cause is cross-jumping, which inserts a jump before the end of the prologue, in fact just before the note; the rest (CFG cleanup, BB reordering, etc) is downhill from there. gcc/ PR rtl-optimization/100411 * cfgcleanup.c (try_crossjump_to_edge): Also skip end of prologue and beginning of function markers. --- gcc/cfgcleanup.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c index 260a896ac486..4086b6475852 100644 --- a/gcc/cfgcleanup.c +++ b/gcc/cfgcleanup.c @@ -2157,7 +2157,11 @@ try_crossjump_to_edge (int mode, edge e1, edge e2, if (NOTE_INSN_BASIC_BLOCK_P (newpos1)) newpos1 = NEXT_INSN (newpos1); - while (DEBUG_INSN_P (newpos1)) + /* Skip also prologue and function markers. */ + while (DEBUG_INSN_P (newpos1) + || (NOTE_P (newpos1) + && (NOTE_KIND (newpos1) == NOTE_INSN_PROLOGUE_END + || NOTE_KIND (newpos1) == NOTE_INSN_FUNCTION_BEG))) newpos1 = NEXT_INSN (newpos1); redirect_from = split_block (src1, PREV_INSN (newpos1))->src; -- 2.47.2